This invention is related to a tool holder assembly having a tool holder and an interlocking cutting tool. The tool holder assembly is connected to a conventional drive spindle. The tool holder includes a cone that is received in a rotating spindle. An elongated body extends from the cone. The cutting tool includes a stepped shank that is telescopically received in the body. A threaded fastener joins the cutting tool to the tool holder body by drawing the cutting tool into a contoured axial opening in the body.
The cutting tool shank and the axial opening include complementary polygonal drive sections that ensure that there are multiple flat surfaces that create an interference fit upon rotation of the cutting tool and resist deflection when the cutting tool is cutting.
Several forms of chucking structures are known for connecting a cutting tool to a rotating spindle, generally using a tapered body that is received in a tapered opening in the spindle.
Art that has addressed this problem include U.S. Pat. No. 4,834,597 issued May 30, 1989 and U.S. Pat. No. 4,934,883 issued Jun. 19, 1990 to Andersson et al.; U.S. Patent Publication No. 2005/0095076 published May 5, 2005 to Pantzar; U.S. Pat. No. 4,7478,879 issued Jun. 7, 1988 to von Hass; and U.S. Pat. No. 5,340,248 issued Aug. 23, 1994 to Ensbergs.
One drawback of some of these prior art tool holders is that their tapered interface between cutting tool and tool holder permit the tool to tilt about or move along the tapered sections (i.e., about an axis that is perpendicular to the longitudinal axis of the tapered section) and become misaligned.
The broad purpose of the present invention is to provide a tool holder chucking structure comprising a minimal number of components while providing a positive drive member and limiting movement of the cutting tool relative to the tool holder.
One advantage of the present invention is that is provides a cutting tool to tool holder interface having two distinct sections: a tapered interface and a polygonal straight interface.
Another advantage of the present invention is that it includes a third cylindrical cutting tool to tool holder interface that resists movement of the cutting tool along the angled profile of the tapered interface.
Still another advantage of the present invention is that it provides a tool holder assembly suited to be removably received into a tapered opening in the spindle of a machine tool. The tool holder assembly including a cutting tool body having means for holding a cutting tool on one end and a shank on the opposite end. This shank includes a triangular drive section. This drive section has three interconnected walls that are each parallel to a longitudinal axis of the shank. A cylindrical shaft extends axially from the drive section and includes a threaded axial bore. The tool holder assembly also includes a tool holder body having an external tapered wall formed about an axial opening and receivable in an opening of a rotatable drive spindle. The axial opening passes through the tool holder body and has a first end with internal threaded means for receiving a retention knob and a second end that is shaped complementary to the shank. Fastening means are also provided and are contained within the axial opening connected to the threaded bore in the cutting tool body to axially move the cutting tool toward the tool holder body and telescopically receive the shank within the second end of the tool holder body.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.